Annular Elastomeric Inserts for Tire Belt Stability

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Solution Overview

Problem

The existing processes for building tires face issues with strip-like elements undergoing uncontrolled deformations and detachment during the laying process, leading to structural instability and potential cracks due to sharp ends from cut metal reinforcing cords, especially when forming belt structures.

Innovation Solution

The use of annular inserts of raw elastomeric material on the auxiliary drum surface, where the ends of strip-like elements are superposed over the inserts, ensuring stable positioning and preventing direct contact with the carcass structure, thereby maintaining structural integrity and reducing production waste.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If strip-like elements are laid directly on the forming drum surface, then the laying process is simple, but the strip-like elements undergo uncontrolled deformations and detachment leading to structural instability

Engineering Contradiction:

Improvelaying process complexityVSAvoidstructural stability of belt structure

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

A separating layer of elastomeric material is introduced between the strip-like elements and the forming drum surface. This intermediary layer prevents direct contact, thereby eliminating uncontrolled deformations and detachment of the strip-like elements while maintaining structural stability, without significantly complicating the laying process.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If metal reinforcing cords are cut to size, then the belt structure can be formed, but sharp ends cause potential cracks and reduce tire quality

Engineering Contradiction:

Improvebelt structure formation efficiencyVSAvoidtire quality uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The elastomeric separating layer is applied beforehand on the forming drum surface, covering the areas where cut ends of metal reinforcing cords would contact the drum. This prior cushioning prevents the sharp cut ends from causing cracks or defects in the tire structure, ensuring uniform quality while maintaining efficient belt structure formation.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Loss of substance

If strip-like elements are positioned without separation, then material usage is efficient, but detachment during laying increases production waste

Engineering Contradiction:

Improvematerial usage efficiencyVSAvoidproduction waste

Core Design Contradiction:

Loss of substanceVSLoss of energy

Solution Approach 1:

A thin film of elastomeric material is applied as a separating layer on the forming drum surface. This thin film prevents detachment of strip-like elements during laying, eliminating production waste, while being efficient in material usage as it forms a continuous thin coating rather than requiring excessive separation materials.

Inventive Principle:

Principle #30Flexible shells and thin films

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution stabilizes the strip-like elements effectively, reduces production waste, and ensures uniformity in tire quality by preventing detachment and cracks, while simplifying the production process and enhancing the rubber-metal bond for improved tire performance.

Implementation Method 1

The ends of a plurality of strip-like elements 20 are then laid down in a known manner onto the laying surface, with respectively opposite end portions radially superposed, each against one of the annular inserts 10

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

Due to the presence of the cross-linking agents, this material can be cross-linked by heating, so as to form the final article of manufacture

Methodology Applied

Scientific EffectCross-linking: Chemical Bonding

Data Source

PatentUS9802376B2Process for building tyres and tyre obtained thereby

Publication Date: 2017.10.31 PIRELLI TYRE SPA

AI summary

A pair of annular inserts of elastomeric material is circumferentially applied by spiraling around a laying surface of an auxiliary drum. Then a plurality of strip-like elements disposed in parallel side by side relationship with each other in the circumferential extension of the laying surface is applied onto the auxiliary drum, so as to form at least one first belt layer. Respectively opposite end portions of each strip-like element are radially superposed, each against one of the annular inserts, so that each of the annular inserts projects from a respective end edge of the strip-like element. The cap structure formed on the auxiliary drum is coupled to a carcass structure through toroidal conformation of the latter, in such a manner that the radially external ends of sidewall portions previously manufactured on the carcass plies are associated with the axially external ends of the annular inserts.